Space transformer connector printed circuit board assembly

ABSTRACT

Space transformer connectors for coupling printed circuit boards and/or other electrical connections are disclosed. A scalar design of a multilayer space transformer connector allows for a variety of pad-array field connections. A conductive elastomer interface provides for repeated and consistent coupling and decoupling of the space transformer connector.

CLAIM OF PRIORITY UNDER 35 U.S.C. §119

The present application for patent claims priority to ProvisionalApplication No. 61/155,082 entitled “3-D SPACE TRANSFORMER (3D-SPACEX)CONNECTOR PRINTED CIRCUIT BOARD ASSEMBLY” filed Feb. 24, 2009, andassigned to the assignee hereof and hereby expressly incorporated byreference herein.

FIELD OF DISCLOSURE

The disclosed embodiments are related to space transformers for couplingprinted circuit boards. In particular embodiments are directed to spacetransformer connector printed circuit board assemblies.

BACKGROUND

Printed circuit boards (PCBs) are the means of choice to interconnect awide variety of electronic circuits and associated components intoelectronic or electro-mechanical assemblies capable of performing anearly unlimited number of tasks ranging from ultra miniaturesurveillance devices to mainframe supercomputers. The PCB assemblies canrange in size from sub-square millimeter to a square meter and beyond.An art form in PCB manufacturing is to reliably produce fine-pitchedcircuits of conductor material (typically copper; CU) on physicallylarge circuit boards, for example, 0.5 mm component pin spacing on a32-layer 18″×24″×0.18″ PCB. Manufacturing these type of PCBs are a featpresently attainable by only a select few PCB fabricators worldwide.This feat becomes highly problematic at a component pin spacing of 0.4mm and smaller and nearly unattainable in designs requiring multiplefine pin-pitch ICs distributed over a large surface area. Greatlyfacilitating sub 0.5 mm circuit geometries and board fabrication yieldis the allowance of smaller/thinner PCBs.

Unfortunately, a small circuit board will rarely hold a large amount ofcircuitry. To merge the best of both worlds, a motherboard (MB)/daughtercard (DC) space transformer technology has developed within theelectronic industry wherein a relatively smaller PCB assembly is mountedatop a larger PCB assembly and electrically interfaced by one or moreconnector means. With this three dimensional approach, board surfacearea immediately adjacent to and directly under the footprint of thesehigh density fine pin-pitch ICs is effectively doubled with top andbottom board surface areas of both the DC and MB available for supportcomponent placement. Prior art MB/DC connections have utilized two-part(male/female) connectors typically of the commercially available typewith some being of the custom variety.

FIG. 1 illustrates a conventional motherboard (MB) 110/daughter card(DC) 120 assembly showing two board-top mounted integrated circuit (IC)sockets 101 flanked by three board bottom-side plug/socket interfaceconnectors (102/112, 104/114, 106/116). The combined assembly is mademechanically integral by the optional use of metal board-joining rails.These board interface connectors may be provisioned to pass signals withfrequencies ranging from DC to multi-GHz. Typically and for a givenconnector size, the signal pin count decreases with increasing frequencyhandling capability as additional ground pins become necessary to assurehigh signal integrity. This reduced pin count becomes problematic withmultiple hundreds to greater than the one thousand pin-count of modernmulti-GHz capable ICs.

SUMMARY

Exemplary embodiments are related to space transformers for couplingprinted circuit boards. Embodiments offer a monolithic high pin-density,high signal integrity (extremely wide band) PCB alternative to two-partconnector prior art. The use of 3D-SpaceX PCB based printed electricalconnectors can afford a higher pin count per unit area compared toalternative connectors.

Accordingly, an embodiment includes a space transformer connector formedof a multilayer printed circuit board comprising: a plurality of groundplanes separated by layers of dielectric material in the PCB; aplurality of conductive vias extending at least partially through thePCB; a pad-array field having a plurality of contact pads located onopposing surfaces of the PCB, which are coupled to the conductive vias;and at least one coaxial mount for alignment and mounting, wherein thecoaxial mount is located adjacent the pad-array field.

Another embodiment includes an assembly comprising a daughter cardcoupled to a device-under-test (DUT) configured to distribute signalsfrom the DUT to a first contact array; a mother board having a secondcontact array; a space transformer connector formed of a multilayerprinted circuit board (PCB) having a connector portion comprising: aplurality of ground planes separated by layers of dielectric material inthe PCB; a first pad-array field having a plurality of contact padslocated on a first surface of the PCB configured to couple to the firstcontact array; a second pad-array field having a plurality of contactpads located on a second surface of the PCB configured to couple to thesecond contact array; a plurality of conductive vias extending at leastpartially through the PCB to couple the first and second pad-arrayfields; and at least one coaxial mount for alignment and mounting,wherein the coaxial mount is located adjacent the first and secondpad-array fields; a first conductive elastomer disposed over the firstpad-array field, wherein the first conductive elastomer is configured toelectrically couple the first pad-array field to the first contactarray; and a second conductive elastomer disposed over the secondpad-array field, wherein the second conductive elastomer is configuredto electrically couple the second pad-array field to the second contactarray.

Another embodiment includes a space transformer connector formed of amultilayer printed circuit board (PCB) comprising: means for providingground connections separated by layers of dielectric a dielectric meansin the PCB; means for providing electrical conductivity extending atleast partially through the PCB; means for providing electrical contacthaving a plurality of contact pads located on opposing surfaces of thePCB, which are coupled to the means for providing electricalconductivity; and means for aligning and mounting in an integrated unit,wherein the means for aligning and mounting is located adjacent meansfor providing electrical contact.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are presented to aid in the description of thedisclosed embodiments and are provided solely for illustration of theembodiments and not limitation thereof.

FIG. 1 is an illustration of a daughter card mounted atop a spacetransformer configuration including a conventional two-part connectorarrangement.

FIG. 2A illustrates a conventional arrangement of connector pin-fieldsand alignment located on opposite ends of a daughter card.

FIGS. 2B & 2C illustrate different arrangements of three 3D-SpaceXconnectors located on opposite ends of a spacer PCB.

FIG. 3 illustrates an arrangement of two 3D-SpaceX connectors located onopposite ends of a daughter card.

FIG. 4A is a detailed illustration of a 3D-SpaceX connector includingdetails of a pad-array field, in one embodiment.

FIG. 4B is a detailed illustration of a portion of the pad-array fieldof FIG. 4A.

FIG. 5 illustrates several alternative configurations 3D-SpaceXconnectors.

FIG. 6 illustrates two circular alternative of 3D-SpaceX connectorslocated on opposite ends a common spacer PCB.

FIG. 7 illustrates an arrangement of two 3D-SpaceX connectors pin-fieldslocated on opposite ends of a daughter card footprint including widebandwidth couplings to RF connectors located on a motherboard.

FIG. 8 illustrates an arrangement multiple superimposed 3D-SpaceXconnector PCB footprints atop a compatible motherboard includingcouplings to RF connectors located on a motherboard.

FIG. 9A illustrates a plan view of two 3D-SpaceX connectors formed on acommon PCB and located on opposite ends.

FIG. 9B illustrates an end view of two 3D-SpaceX connectors formed on acommon PCB and located on opposite ends.

FIG. 10 illustrates an arrangement of multiple 3D-SpaceX connectorsformed on a common PCB.

FIGS. 11A-C illustrate various aspects of the construction of a3D-SpaceX connector including a conductive elastomer interface andexample PCB via construction illustrating multiple signal ground planes.

FIG. 12 illustrates a side view of an arrangement multiple integral3D-SpaceX connectors and daughter card formed on a common PCB.

FIG. 13 illustrates an assembly for an integrated circuit test systemincluding individual (free-standing) 3D-SpaceX connectors.

FIGS. 14A and 14B illustrate an assembly for a circuit test systemincluding 3D-SpaceX connectors, a coaxial mounting and a two-mountsocket.

FIGS. 15A-15C illustrate a configuration of 3D-SpaceX connectors havingedge connectors and an internal shelf.

FIGS. 16A-16C illustrate a configuration of 3D-SpaceX connectors havingedge connectors, an internal shelf and a pedestal arrangement.

DETAILED DESCRIPTION

Aspects are disclosed in the following description and related drawingsdirected to specific embodiments. Alternate embodiments may be devisedwithout departing from the scope of the invention. Additionally,well-known elements of the disclosed embodiments will not be describedin detail or will be omitted so as not to obscure the relevant detailsof the disclosed embodiments.

The word “exemplary” is used herein to mean “serving as an example,instance, or illustration.” Any embodiment described herein as“exemplary” is not necessarily to be construed as preferred oradvantageous over other embodiments. Likewise, the term “embodiments”does not require that all embodiments include the discussed feature,advantage or mode of operation. Further, the dimensions illustrated andapplications discussed herein are merely for illustration of embodimentsand do not limit the embodiments to these specific examples.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of embodiments. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”,“comprising,”, “includes” and/or “including”, when used herein, specifythe presence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof. As used herein the terms 3D-SpaceX,3D-SpaceX connector and space transformer connector may be usedinterchangeably.

In the illustrated embodiments provided herein, some dimensionalinformation is provided to give a reference to the scale and relativesizes of elements in various embodiments. However, these examples andillustrations are provided solely to facilitate discussion andunderstanding of embodiments and are not to be construed as limitingembodiments to the disclosed dimensions, scale, and/or relative sizes ofelements.

As illustrated in the disclosed embodiments, a daughter DC and MB aremechanically arranged and the circuit is configured to sandwich adiscrete-signal electrically conductive three-dimensional PCB based highdensity pad-array field space transformer connector (3D-SpaceX) betweenthem. A 3D-SpaceX connector (or connector portion) is generally usedherein as the combination of pad-array field, PCB mounting and alignmentfeatures, and any feature(s) used to accommodate a conductive mediumbetween the pad-array field electrical interface between the connectorportion and the DC and/or MB. As used herein the term pad can include apin/contact on a surface of a PCB which may be coupled to conductivevias which provide for conduction of the electrical signal inside andthrough the PCB. The pad-array (or pin-array) is defined herein as anarrangement of electrical pad/pins/contacts within a pad-array field.DC/3D-SpaceX/MB interface continuity is established and sustainedsubject to a compression force typically provided by a spring-loadedalignment/restraint mechanism. The 3D-SpaceX Space Transformer includesone or more PCB based pad-array field connectors ranging in thicknessfrom less than 2 mm to greater than 10 mm. Additionally, a spacetransformer connector as used herein may include one 3D-SpaceX connectorportion and additional portions formed from a common PCB.

The 3D-SpaceX connector itself in embodiments includes a two-sidedmulti-layer circuit board configured with one or more opposing surfacepad-arrays interconnected by conductive vias. Depending upon the3D-SpaceX connector physical-electrical combination of pad, via,anti-pad, location/separation of parallel internal ground planes, numberand location of signal grounds and, of course, the requisite insulatordielectric constant and loss tangent, individual connection electricalproperties may be optimized to accommodate virtually any signal typeranging from high-current power and ground capable to thoseultra-wideband signals found in multi-gigahertz frequency radiocommunications. Pad-array field pin/pad densities may be limited only byapplication specific requirements. For example, high current and/orvoltage applications may require widely separated large pin pads andvias due in part to thermal considerations or dielectric high-potstrength resulting in only a few pads per square inch while low currentsignal connectivity may push pad count well beyond 2600 over the samesurface area. The arrangement of 3D-SpaceX connector opposing conductiveinterconnected pads are replicated upon both the DC and MB electricalconnection areas in some embodiments. In some embodiments, two or morespace transformer connectors are free-standing (stand alone) connectorsfabricated from the same or differing PCB material. Another exemplaryembodiment includes fabricating the space transformer connector and allconnector portions from a single monolithic PCB material and to machinethe board space between connectors in a combination of entirely throughboard, to effectively mechanically isolate each connector portion, andcan include optional device under test (DUT) integrated socket mountingpedestals and/or a DUT-center support pedestal. The DC/3D-SpaceX/MBinterface can formed of a compressible electrically conductive mediumwhich may include but is not limited to, spray-ons, conductiveelastomers, or other suitable conductive elastomeric materials.

FIG. 2A illustrates a bottom view of a daughter card 200 that caninclude an area for mounting a socket for holding DUT 250 and one ormore electrical connection areas 213 for mating connectors electricallycouple DUT related signals to a motherboard. As used herein, DUT 250will generally be interchangeably referred as either including thesocket mount for the device under test or for direct device solderattachment for convenience of explanation. Additionally, it can beappreciated that embodiments may serve to support two or more DUTlocations (not shown).

Each connector mating connection area 213 can include pins 212 thatcontains a plurality of connecting points for coupling daughter cardsignals to a motherboard or other electrical connection. Conventionalmounting configurations include separate alignment points 216 andmounting points 218. As will be appreciated, two guide and mount points216 can be used for registration (alignment) of a connector to thedaughter card 200.

Referring to FIG. 2B, for example, embodiments of the spacer connector202 include mounting and alignment functions may be included in onecoaxial mounting element as discussed further herein. In contrast to theconventional configurations have utilized two discrete pin-fieldalignment means (e.g., 216) and four or more compressive mounting points(216, 218) per connector (see, e.g., FIG. 2A). As an alternativeexample, the daughter card/3D-SpaceX PCB/mother board mechanicalcoupling may be achieved by a gluing a pressure application mechanism tothe MB

It will be further appreciated, referring to FIG. 2B, for example, thatthe 3D-SpaceX connectors are not necessarily symmetrical in physicalarrangement (e.g., size, shape and/or orientation) and/or electricalarrangement (e.g., pad-array field arrangement), but are configured toalign to corresponding contact pads of a daughter card and/or motherboard. For example, as illustrated in FIG. 2B an embodiment of a spacertransformer connector (3D-SpaceX PCB) 202 can have first 3D-SpaceXconnector 220 that is orientated substantially parallel to DUT cutout260 and a second 3D-SpaceX connector 222 on an opposite side of DUTcutout 260 that is orientated at an angle relative to DUT cutout 260. Inan exemplary embodiment milled or formed glue channels 224 are providedto mechanically attach a conductive elastomer (not shown) that isoverlaid on each 3D-SpaceX connector pad-array surface (second surfacenot shown) to form the coupling points for the 3D-SpaceX connector tothe DC and MB connection surfaces. In an alternative embodiment, aconductive elastomer is affixed to glue channels located about DC and MBpad-arrays and none affixed to either side of the 3D-SpaceX connectorinterface. In another example of embodiments, as illustrated in FIG. 2C,a 3D-SpaceX assembly 203 includes circular 3D-SpaceX connectors 230, 232on opposite sides of DUT cutout 260. In an embodiment, conductiveelastomers are stretched and glued over a circular frames 234 (opposingside frame not shown) then placed into circularly milled grooves oneither side of each 3D-SpaceX connector to overlay opposing pad-arraysurfaces. Further as illustrated, each 3D-SpaceX connector 230, 232 hasa different electrical arrangement. For example, 3D-SpaceX connector 230has a pad-array field containing 1077 pins and 3D-SpaceX connector 232has a pad-array field containing 1049 pins. Accordingly, it will beappreciated that embodiments can include any combination of physical andelectrical arrangements for the 3D-SpaceX connectors.

Referring to FIG. 3, another configuration of a 3D-SpaceX connectorarrangement is illustrated. In this configuration a monolithic spacetransformer connector 300 has 3D-SpaceX connectors 310, 320 (connectorportions) located on opposite sides of a DUT cutout area 260. 3D-SpaceXconnectors 310, 320 have generally parallelogram shaped pad-array fields(e.g., 312, 322). However, the pad-array field arrangement for 3D-SpaceXconnector 310, is the inverse (mirrored image) of the 3D-SpaceXconnector 320. Additional aspects of the 3D-SpaceX connectors 310, 320will be described in relationship to 3D-SpaceX connectors 310 only toavoid unnecessary repetition.

The pad-array field 312 of 3D-SpaceX connector 310 includes a pluralityof high frequency/wideband pin connections 311. Additional detailsregarding the wideband pins will be discussed below. 3D-SpaceX connector310 also includes glue channels 314 for holding down an elastomericconductor which serves as the electrical coupling point for pad-array312. Further, 3D-SpaceX connector 310 includes two coaxial mounts 315,which provide both alignment and mounting for 3D-SpaceX connector 310.The use of the term “coaxial mounts” herein is defined as thecombination of DC, 3D-SpaceX, and MB PCB alignment and compressivemounting means provided along a common z-axis line perpendicular to thex-y plane of the PCB sandwich illustrated in FIG. 13 and discussionthereof below. This means holds the distinct advantage in the reductionof the number of PCB hardware clearance features required. Minimizingthe number and size of these features significantly increases tracerouting area and resultant trace density as well as affording ampletrace isolation as needed.

FIG. 4A is a detailed illustration of a pad-array field arrangement of a3D-SpaceX connector. Similar to the pad-array field described above inrelation to FIG. 3, the 3D-SpaceX connector 410 includes a plurality ofwideband pin connections 411. Additionally, the 3D-SpaceX connector 410also includes glue channels 414 for holding down an elastomericconductor. It will be appreciated, that a keepout region 430 can beprovided adjacent the glue channels to prevent contamination of thecontacts from the adhesive used to secure the conductive elastomer. Inthe example embodiment, a 2 mm region is provided around the entirepad-array. However, it will be appreciated that this example is merelyprovided for this illustration and the width and length of the keep-outregion may be adjusted to accommodate the specific configuration of thepad-array and glue channels. Further, 3D-SpaceX connector 410 includestwo coaxial mounts 415, which provide both alignment and mounting for3D-SpaceX connector 410. Each coaxial mount 415 may be formed from ametal insert. Alternatively, coaxial mount 415 may be formed of anon-metal insert. Regardless of the configuration, coaxial mount 415 isconfigured to provide for a precise alignment interface to the adjacentelements (e.g., mother board and/or daughter card). For example, aninsert used to form coaxial mount 415 may be machined, molded, etc. toachieve a precise internal dimension that can be used for alignment toadjacent elements (see, e.g., FIG. 13). Further, in configurations whereit is desired to have compressive force applied internally, coaxialmount 415 may include an inner threaded element that allows for asmaller fastener to be inserted for purposes of supplying compressiveforce while a larger inner precision inner diameter of coaxial mount 415can be used for alignment purposes. It will be appreciated that forstandalone 3D-SpaceX connectors, both coaxial mounts are used formounting and alignment. However, in other embodiments where two or more3D-SpaceX connectors are part of a space transformer connector, onlyopposite end corner coaxial mounts may be used for alignment purposes.Once again, the mounting configuration is provided merely to illustrateaspects of the embodiments and the scope of the invention is not limitedto any specific configuration illustrated.

The ultra wideband contact pads/pins 411 are generally arranged tosimulate a coaxial cable configuration. For example, pin 440 groupconfiguration geometry can have one or more ground pins 442 adjacent thewideband signal pin 440. In the illustrated configuration, three groundpins 442 are placed symmetrically around the wideband pin 440.Additionally, wideband pin 440 can be configured to include an antipad.In one example, an antipad is an area where the dielectric coppercladding has been removed so there is no copper surrounding the signalvia throughout all PCB inner layers. Embodiments may include anycombination of signal and ground vias, via geometry, and one or moreantipad characteristics. Accordingly, the wideband pins 411 can providefor minimal degradation of high frequency signals. Internal arrangementsof the connector including the antipads are illustrated in relation toFIG. 11C.

FIG. 4B illustrates the details of other portions of the pad-array 412,where the contact pad (connected as signal pins or ground pins) areconfigured in a ground/signal/ground (GSG) configuration 450. Forexample, each/signal pin 451 is adjacent a ground pin 452 in rows 450.The signal pin 451 can also be configured inclusive of an antipad 454,as discussed above. Further, in another aspect, the arrangement of thesignal and ground pins in adjacent rows can be alternated such thatsignal pins oppose ground pins. In this embodiment, signal bandwidth ismaximized for a given PCB pad-array field construction. Further, rows450 of pad-array field 412 may be oriented at an angle and separated ata distance to facilitate additional high density copper-to-copper(CU-CU) routing opportunities between daughter card DUT and 3D-SpaceXpad-array as with the three traces 460 routed between pad rows. Thedegree of row separation and inclination in relation to the PCB materialmechanical and electrical characteristics relates to the number andwidth of adjacent traces allowable as detailed in FIG. 4B.

FIG. 5 illustrates a variety of space transformer connector pad-arrayfield configurations. The example space transformer connectorsillustrated have a variety of geometric pad-array fields, and mountingconfigurations and geometries such as square (508), rectangular (507),or trapezoidal (501-506). Pad-array field/contact pad placement includesregular (uniform) to random patterns with segmented and non-segmentedpad-array group geometries not limited to circular, rectangular, square,trapezoidal, parallelogram, N-sided convex and concaved polygons, andfree-form pad-array fields and the like. Accordingly, it will beappreciated that embodiments are not limited to any specific geometricpad-array field and mounting configuration and that the illustratedexamples are provided merely for illustration of aspects and flexibilityof the embodiments.

FIG. 6 illustrates two circular 3D-SpaceX connector portions 610 and 620on a space transformer connector 602 formed from a monolithic PCB. Eachconnector portion is shown with two mounting and alignment features 615oriented as in one embodiment. It will be appreciated that theembodiments are not limited to any specific mechanicalalignment/mounting orientation. Pad-array fields 612 and 622 are shownoriented with wideband contact pads/pins 611 directed towards the centerof the DUT area cutout 660 to facilitate short low loss DUT to MB signalconnectivity. The pin-arrays 612 and 622, as shown, are in anarrangement of equidistant pad rows and columns but may be configuredthe same or uniquely as needed on an application specific basis. In anembodiment, DUT (and possibly DUT support circuit) direct current power(PWR) and ground (GND) connections 642 of 3D-SpaceX connectors 610 and620 are shown for illustration in two locations within the each3D-SpaceX connector as 16-PWR/GND supply inputs; in connector 610,directly opposite wideband pads 611 and in 620, directly behind widebandpads 611. Although locating PWR & GND pins in either of the twolocations shown is an exemplary embodiment any location within thepad-array field is embodied as well as the increase, decrease, orelimination PWR/GND connections altogether. These examples andillustrations are provided solely to facilitate discussion andunderstanding of embodiments and are not to be construed as limitingembodiments. In the example embodiment of FIG. 6 conductive elastomersmay optionally be stretched and glued over circular frames 634 thenplaced into circularly milled grooves on either side of each 3D-SpaceXconnector PCB 602 to overlay opposing pad-array field surfaces. Milledgrooves (not shown, but similar to 414, for example) can be made of adepth slightly exceeding elastomer frame thickness to ensure theco-planarity and requisite integrity of the 3D-SpaceX to DC/MBelectro-mechanical interface.

In the embodiment of FIG. 6 the example of opposing locations of the twomounting and alignment coaxial mounts 615 may be oriented about thecenter of each 3D-SpaceX connector location on an application specificbasis. Further, in applications for which the 3D-SpaceX mechanicalmounting and alignment features must be fixed, for example across agiven product line, the circular embodiment of the 3D-SpaceX connectorpad-array field may be rotated about its axis to establish idealwideband pin 611 ingress and egress with respect to corresponding DUT(and/or DUT support circuits) high speed signal placement.

Further, FIG. 6 illustrates a milled DUT cutout area 660 that may berelieved entirely of its board center material or optionally include aremote integrated mount 680, 682, 684 for mounting the space transformer602, which is remotely locate relative to the coaxial connector mounts615 and separated from connector mounts by removed portions 603 and 606.The remote integrated mount may also be used for mounting/coupling toother devices, for example, DUT socket mounting supports 680 (2-places),682, 684 and optional DUT center pedestal support 670 for applicationsrequiring DUT socket to MB (through DC and 3D-SpaceX PCB) attachment andDUT center support in certain automatic DUT handling applications.Additionally, the DUT center support may be configured to provideelectrical shielding (e.g., by using metal layer in the PCB) between theDUT and top of the MB. DUT center support bridge 672 can also optionallybe milled thin from either side or both to the point that the DUT centersupport remains mechanically integral to the space transformer connector602, yet permits the extensive placement of DC bottom-side circuitcomponents in close proximity to the DUT footprint or to better utilizeMB top surface component placement.

FIG. 6 additionally illustrates extensive PCB milling, in addition tothat within the DUT cutout area 660, immediately adjacent to (includingaround the sides of) 3D-SpaceX connectors (connector portions) 610 and620. The advantage of this milling is two-fold; first, to improveco-planarity of mating surfaces and ensure an integralelectro-mechanical connector interface and, second, to minimize “SkinEffect” trace signal loss in wideband signal routing. Although detached(free-standing) 3D-SpaceX connectors, when individually fabricated fromdiffering PCB material lots and then applied in an application of two ormore connectors are an embodiment of this invention, respectiveconnectors may have differing overall thicknesses. When discrete3D-SpaceX connectors are used in close proximity, differing connectorthicknesses may compromise MB/3D-SpaceX/DC interface co-planarity.Fabricating two or more 3D-SpaceX connectors on a common monolithic PCBsubstrate effectively eliminates (i.e., significantly reduces) nonco-planarity issues resulting from varying connector PCB thicknesses. Inaddition, the application of PCB milling such as to those shown in FIG.6 effectively mechanically isolates each 3D-SpaceX connector allowing itto freely establish its own mechanical steady state position. Eachconnector is effectively independent of all others as well as from theintegrated DUT socket mounting if utilized.

As is known to those skilled in the art, Skin Effect losses increasewith decreased electrical conductor geometry and increased dielectricconstant (greater than that of air) of trace adjacent insulators. Narrowimpedance controlled traces sandwiched between PCB dielectric instripline fashion have a higher skin effect loss than those of wide PCBsurface microstrip traces of the same impedance. As such, bottom-side DCsignal conductors configured as impedance controlled microstrip traces(wherein air is an adjacent trace dielectric) afford the most optimalsignal handling characteristics attainable in a PCB environment. Bymilling out as much of the 3D-SpaceX PCB material as possible aroundeach 3D-SpaceX connector, the amount of surface conductor for which airas a dielectric is maximized.

FIG. 7 illustrates a configuration of a daughter card footprint,superimposed over 3D-SpaceX 710, 720 connectors and motherboard withradio frequency (RF) connectors placed and trace-connected to the MBwideband pad-array pins. Only the MB RF connectors are illustrated indetail, however, it will be appreciated that the motherboard componentsand features (not shown) may include a variety of other elements,connectors, and the like. The daughter card 700 (footprint shown in thefigure) contains a DUT 250, and 3D-SpaceX connector pin-fields, such asdiscussed in relation to the previous embodiments, accordingly commonelements will not be recited or explained in detail. The wideband pins711 can be configured to couple to wideband/high frequency connectionsto the motherboard which are coupled to the RF connectors 760 and 770,which are mounted on a bottom side and through to the bottom side from atop side of the motherboard, respectively. The RF connectors 760 and 770are located on an arbitrary first and second radius and the RFconnectors can be staggered from top to bottom in an alternating pattern(e.g., every other connector is on the top or bottom of themotherboard). Doing so improves adjacent wideband connection isolation.It will be noted that RF connectors placed along a radius about acircular 3D-SpaceX connector embodiment (e.g. 610, FIG. 6 and the like),afford ease of equal length transmission trace routing to a widebandpad-array field when required.

FIG. 8 illustrates an arrangement of four daughter card footprintssuperimposed over respective 3D-SpaceX connectors and individualmotherboard locations having radio frequency (RF) connectors placed andtrace connected to each MB wideband pad-array field. Each daughter cardcontains a DUT 250, and 3D-SpaceX connector pad-array field, such asdiscussed in relation to the previous embodiments. Accordingly, fourDUTs can be tested in a compact form, as each daughter card and itsassociated RF connections are contained within a uniform profile (e.g.,40 mm by 90 mm as illustrated). Further, embodiments facilitate thesupport of multiple DUT rows (not shown) by the placement of two or moreDUTs vertically and including one or more 3D-SpaceX connectors betweenthem. Accordingly, embodiments include support for an array of DUTs inboth the x and y dimensions.

FIG. 9A illustrates two 3D-SpaceX connectors (connector portions) of aspace transformer connector 900 formed of common PCB material andlocated on opposite ends of space transformer connector 900. Asillustrated, space transformer connector 900 surfaces are co-planar andof uniform thickness under the two 3D-SpaceX pad-array fields, edgeextremities, and optional integrated DUT mounting pads 980 and pedestal970. The integrated DUT mounting pads 980 also form a remote integratedmount in relation to 3D-SpaceX connectors 910, 920 and may be used invarious embodiments with or without the DUT pedestal and with one ormore 3D-SpaceX connectors to provide a remote mounting location. The PCBmaterial of space transformer connector 900 can be extended beyond the3D-SpaceX connector portion and may be milled out (or otherwise have thematerial removed) in portions (e.g., 902 and 904) immediately adjacentto the 3D-SpaceX connectors 910, 920. Portions 902 and 904 that have allmaterial removed, may substantially extend around the perimeter (e.g.,three sides or at least half of the perimeter) of each 3D-SpaceXconnector, so only a portion of the 3D-SpaceX connector is coupled tothe remaining PCB material of space transformer connector 900.

Further, the remaining areas of space transformer connector 900 may bereduced in thickness for various portions. For example, 908 locatedunder the DUT mounting area can be milled thinner than portions 906,outside the DUT mounting area. Using a configuration similar to thatdetailed in FIG. 6, for example, coaxial mounting points 912, 914 of thefirst 3D-SpaceX connector 910 form a mounting frame of reference aboutwhich the 3D-SpaceX connector 910 can independently physically locate(e.g., connector portion 910 is relatively free floating in relation tothe remote integrated mount 980. Likewise, coaxial mounting points 922,924 of the second 3D-SpaceX connector 920 form a separate mounting frameof reference about which the 3D-SpaceX connector 920 can locateeffectively independent of the first connector 910. Accordingly, nonco-planarity between the mounting surfaces (e.g., daughtercard/motherboard) can be accommodated for by each of the 3D-SpaceXconnectors 910, 920. Additionally, by allowing portions 902 and 904 tobe open, conductive traces including pads (e.g., on the bottom of thedaughter card) can get the approximate properties of micro-strip withair being the dielectric.

FIG. 9B illustrates an end view through section A of space transformerconnector 900. As illustrated and discussed above, area 908 locatedunder the DUT mounting is milled thinner than portions 906, outside theDUT mounting area. This reduced thickness under the DUT can providespacing for surface mounted components on the daughter card and/ormotherboard. Further, although only milled on one side as illustrated,it will be appreciated that either side or both sides can have materialremoved to provide a reduced thickness and clearance for adjacent DC/MBelements.

As noted above, two or more 3D-SpaceX connectors can be formed spacetransformer connector 1000 formed from a common circuit board (PCB).FIG. 10 illustrates an arrangement of multiple 3D-SpaceX connector pairsall fabricated from and located on a common circuit board of spacetransformer connector 1000. Since the 3D-SpaceX connectors are made froma common circuit board, the thickness of each of the 3D-SpaceXconnectors can be controlled, which can help to mitigate variations dueto 3D-SpaceX connectors being made from different circuit boards.However, it will be appreciated that the embodiments are not limited tothe illustrations of FIGS. 9A and 10. For example, as discussed above,the number of 3D-SpaceX connectors and DUT locations may be expandedinto a row/column array of DUTs. Alternatively, as illustrated in otherembodiments each 3D-SpaceX connector can be formed on separate circuitboards.

Further, it can be appreciated that if each of the 3D-SpaceX connectorsshown in FIG. 10 were configured as in the FIG. 6 circular connectorembodiment, a circular pad-array field equal in area to theparallelogram connectors shown would afford a much greater connector toconnector separation distance. For example, assigning each FIG. 10connector pin-array a 3×2 cm x-y dimension (a 6 square-cm area) withpad-array field centers separated by 4 cm, the 3D-SpaceX edge to edgeconnector spacing would be 1 cm. Circular 3D-SpaceX connectors of 6square-cm area each would yield a nearly 1.24 cm edge to edgeseparation. This additional separation distance greatly enhances MBrouting area between 3D-SpaceX connectors. Once again it will beappreciated that pad-array field geometry and pin configurations areprovided merely for illustration and that embodiments mayinterchangeably use the various pad-array field geometry and pinconfigurations as desired for a specific applications.

FIG. 11A illustrates a plan view of spacer transformer connector 1110(embodied as a standalone 3D-SpaceX connector) illustrating thepad-array field 1112 and glue channels 1114 prior to the addition of aconductive elastomer. FIG. 11B is a perspective view of the 3D-SpaceXconnector 1110 with top conductive elastomer 1120 and bottom conductiveelastomer 1130 adjacent to the surfaces they are adhered to. Forexample, in assembling 3D-SpaceX connector 1110 top conductive elastomer1120 can be stretched and secured to glue channel 1114, which providesfor adhesion of conductive elastomer 1120 to ensure that pad-array field1112 is uniformly covered by the conductive elastomer 1120. The bottomconductive elastomer 1130 can be secured to the bottom of 3D-SpaceXconnector 1110 via similar glue channels, which are not illustrated.With attached elastomer coverings on either side of each 3D-SpaceXconnector no separate framed elastomer piece-parts are required.Further, at least two of four mating surface interfaces (the contactpads in on pad-array field 1112) benefit by having the conductiveelastomers 1120 and 1130 form integral pad-array field dust covers onthe top and bottom pad-array fields 1112.

FIG. 11C illustrates a sectional view of a portion of the 3D-SpaceXconnector 1110. In one embodiment, the 3D-SpaceX connector can be madeup of a multilayered PCB having a plurality of ground planes 1170separated by layers of dielectric material 1172. Further, additionalconductive planes/traces may be included internally separated bydielectric layers for routing signals internally. Conductive ground vias1162 and signal vias 1164 can run substantially perpendicular to theground planes 1170. Each via is connected to contact pads 1168 affixedto it at each PCB surface. The ground vias 1162 can be coupled to theground planes, whereas the signal vias 1164 may have antipads 1165formed in each ground plane. This arrangement provides for coaxial-typeperformance to contain the electrical fields of the signal vias 1164.Further it will be appreciated that in various embodiments a firstcontact pad may be coupled to a conductive via that may extend onlypartially through the PCB to an internal connection point and may berouted from there to one or more conductive vias that couple to one ormore pads that may be physically offset from the first contact pad.Accordingly, embodiments include configurations where the coupledcontact pads on either side of the space transformer connector 1110, maybe physically offset from each other.

The conductive elastomer 1120, 1130 provides for a contact between thepad-array field and electrical connections on a mating surface (e.g.,bottom of daughter card). For example, when the daughter card, spacetransformer connector 1170, and MB are mechanically coupled together thepressure of the clamping force allows for the connection from thepad-array field 1112 to contact both the contacts on the daughter cardand motherboard, without the need of any permanent connections (e.g.,soldering) or bulky/complex electro-mechanical connection, such as inthe plug and socket configuration of FIG. 1. The conductive elastomermay be in a sheet form, a spray-on material, or any other similar highdensity conductive compressible material, that becomes conductive invertical paths under pressure.

FIG. 12 illustrates an embodiment where a daughter card 1220 and3D-SpaceX connector portions 1210 a-c are integral being formed from acommon PCB of space transformer connector 1200. In this configurationthere would be no need for a conductive elastomer between the integrateddaughter card 1220 and 3D-SpaceX connectors 1210 a-c, as they wouldalready be a single entity. Accordingly, a conductive elastomer withglue channel or other type of conductive medium and its requisitesupport structure(s) as necessary would be used on the surfaces of the3D-SpaceX connectors 1210 a-c that are opposite the daughter cardportion 1220. Each connector portions 1210 a-c has a pad-array fieldhaving a plurality of contact pads which are coupled to conductive vias.The connectors 1210 a-c comprises a plurality of ground planes separatedby layers of dielectric material in the PCB as in the other spacerconnector embodiments. However, the PCB material extends beyond theconnectors 1210 a-c and includes layers forming the daughter card 1220.Coaxial mounts (1215 a, b) can be provided at opposite ends foralignment and mounting. Each coaxial mount 1215 a, 1215 b can be locatedadjacent the pad-array field of respective connector portions 1210 a,1210 b. Once again, the dimensions in the illustrated example areprovided to aid an appreciation of the scale in one example and are notto be construed as limiting the scope of the embodiments.

Conventional configurations have utilized two discrete pin-fieldalignment means and four or more compressive mounting points perconnector (see, e.g., FIG. 2A). Embodiments of the space transformerconnector include variants of which are based on a monolithic PCBconstruction or formed of one or more individual free-standing(discrete) PCB connector(s) (3D-SpaceX connectors). Each may use as fewas two compressive mounting points per pin-field as dictated by thepin-array group geometry. In the monolithic PCB spacer transformerconnector configurations, the “linked” pad-array fields (see, e.g.,FIGS. 2B-C, and 7) is suitable for applications in which moderatelyco-planar daughter card and mother board PCB surfaces are present. Fortwo-connector linked pad-array fields spacer transformer connectors,only one combined mounting/alignment point is required per connectorportion (adjacent the pad-array field) and may be located at oppositecorners of the extreme ends of the monolithic spacer transformerconnector PCB. In the case of three or more linked-pin-field connectorsper spacer transformer connector PCB (e.g., FIG. 12), again only the twoopposing maximally separated mounting points may be fashioned withintegral alignment features (e.g., coaxial mount 415). Additionalintegral intra PCB connector linked-pin-field location(s) can beprovisioned with a pair of daughter card/3D-SpaceX connector onlyalignment features along with mother board/daughter card/3D-SpaceXconnector compressive retainers.

The “floater” pad-array field/connector portions configuration (see,e.g., FIGS. 6 and 9A) is suited for applications in which the motherboard and/or daughter card surface co-planarity is suboptimal. Withessentially free-floating pad-array field/connector portions (butloosely coupled by space transformer connector PCB), the floaterconfiguration of the 3D-SpaceX connectors utilize two motherboard/daughter card/3D-SpaceX mounting and alignment combined points(e.g., coaxial mounts 415) within each connector portion irrespective ofthe number of connectors per space transformer connector PCB. Lastly,discrete space transformer connectors (stand alone 3D-SpaceX connectors)afford advantages similar to the floater pin-field connector but may beless expensive to fabricate. Also, discrete connectors of differingfabrication may be used within the same application for specializedsignal transmission, current carrying characteristics and the like.Applications utilizing this discrete connector type should considerindividual 3D-SpaceX connector PCB thickness variations whenanticipating overall system mechanical tolerance limits.

FIG. 13 illustrates an example of a test assembly including spacetransformer connectors 1310 in a free-standing (discrete) configuration(e.g., standalone 3D-SpaceX connectors). As will be appreciated,3D-SpaceX connectors 1310 including the conductive compressible medium1315 (on both daughter card and mother board side of 3D-SpaceXconnectors 1310) allow for repetitive coupling and decoupling ofelectrical connections with high signal integrity, which is well suitedfor integrated circuit (IC) testing assemblies among other applications.In the configuration illustrated, the 3D-SpaceX connectors 1310 providethe interface between daughter card 1320 and motherboard 1330. Theassembly of the 3D-SpaceX connectors 1310, daughter card 1320 andmotherboard 1330 can be mechanically coupled using a coaxial mountingand alignment arrangement as illustrated. For example, fasteners 1332and 1334 may provided compressive force for the assembly and may also beused for alignment purposes between the mother board 1330 and the3D-SpaceX connectors 1310 via the coaxial mounts. At the daughter card1320 interface fastener 1332 provides for alignment while the reduceddiameter portion of 1334 provides for compressive force without a strictalignment interface. It will be appreciated that the mounting meansdepicted is for illustration purposes only. Any number of methods may beutilized to provide requisite compressive force across the 3D-SpaceXconnector interface. Additionally, as illustrated in FIG. 13, a testadapter mechanism 1340 can be used in combination with device-under-testsocket and carrier (DUT) 1350 to rapidly load and test ICs, as is knownin the art.

As was mentioned in the foregoing, and illustrated in some of theexamples, embodiments can include coaxial mounting configurations toreduce the number of mechanical connections between the socket mount/DUT1450, daughter card 1470, space transformer connector 900 andmotherboard 1490. FIG. 14A is an illustration of an assembly including apartial illustration of space transformer connector 900 (e.g., asillustrated in FIG. 9A) and coaxial mounting assemblies 1410 and 1420,which can be used to secure the assembly 1400 including socket mount1450, which is further illustrated in FIG. 14B. Details regarding thecoaxial mount and socket are provided in U.S. patent application Ser.No. 12/543,373, entitled “Two-Mount and Three-Mount Socket Design withCoaxial Attachment and Alignment” filed Aug. 18, 2009, and assigned tothe assignee hereof and hereby expressly incorporated by referenceherein.

Accordingly, in view of the foregoing it will be appreciated thatembodiments can include assemblies (e.g., as illustrated in FIGS. 13 and14) including a daughter card (1320, 1470) coupled to adevice-under-test (DUT) (1380, 1450) configured to distribute signalsfrom the DUT to a first contact array to a mother board (1330, 1490)having a second contact array via a space transformer connector (1310,900). The space transformer connector (1310, 900) can be formed of amultilayer printed circuit board (PCB) having a connector portion, asdescribed in the foregoing embodiments.

For example, the connector portion (1310, 910, 920), can include aplurality of ground planes separated by layers of dielectric material inthe PCB. A first pad-array field (e.g., top side of connector portions910, 920) can have a plurality of contact pads located on a firstsurface of the PCB configured to couple to the first contact array ofthe daughter card and a second pad-array field (e.g., bottom side ofconnector portions 910, 920) can have a plurality of contact padslocated on a second surface of the PCB configured to couple to thesecond contact array on the mother board (1330, 1490). The connectorportions (910, 920) can further include a plurality of conductive vias(e.g., as illustrated in FIG. 11C) extending at least partially throughthe PCB to couple the first and second pad-array fields and at least onecoaxial mount (e.g., 912, 922) for alignment and mounting locatedadjacent the first and second pad-array fields. A first conductiveelastomer (e.g., 1315, 1120) can be disposed over the first pad-arrayfield to electrically couple the first pad-array field to the firstcontact array. A second conductive elastomer (e.g., 1315, 1130) can bedisposed over the second pad-array field to electrically couple thesecond pad-array field to the second contact array.

It will be appreciated that the various pad-array field configurationsand space transformer connector configurations (e.g., linked, floater,discrete) may be used in circuit board assemblies and the discussionsand illustrations provided herein are not intended to limit theembodiments. For example, the two-mount socket (e.g., 1450) assembly ofFIG. 14 can be combined with a space transformer connector of FIG. 9including an integrated mount portion formed from the PCB (980)configured to couple and align with the two coaxial mounts of thetwo-mount socket (1410, 1420). Further, the various features of thespace transformer connectors discussed herein may be advantageouslyemployed in various assemblies. For example, a portion of the PCB (902,904) can removed from an area between the connector portion and theintegrated mount portion (980) to mechanically isolate the connectorportions (910, 920) from the DUT/socket mount location to achieve arelatively independent mechanical steady state position in relation tothe integrated mount portion (980) adjacent DUT support pedestal (970).Further, as discussed in relation to FIG. 9, the DUT support pedestal(970) can have PCB material milled away adjacent the DUT supportpedestal to allow for placement of electrical components adjacent theDUT pedestal and/or the DUT support pedestal (970) can be configured toprovide electrical shielding. Once again, embodiments are not limited tothe discussed or illustrated combinations and one skilled in the artwill appreciate the interchangeability and application of the variousembodiments of space transformer connectors disclosed herein.

In further embodiment, FIGS. 15A-C illustrate a configuration of thespacer transformer connector 1500 having at least one PCB edge connector(e.g., 1510 a-c, 1520 a-c) to permit external connections to selectedsignals passing between the daughter card and the mother board.Referring to FIGS. 15A-C in addition to edge connectors 1510 a-c and1520 a-c, a shelf 1530 may be formed to support the addition of one ormore active/passive components (e.g., 1560 and 1565) directly coupled tothe PCB forming the space transformer connector. The components 1560 and1565 in embodiments may be located on either side of the shelf portion1530. The active/passive components can be used for integral signal bandlimiting/shaping functions and may be comprised of lumped and/ordistributed elements.

In some embodiments the shelf 1530 may be formed from the same portionthat is used for the edge connectors 1510 a-c and 1520 a-c. A cut-outportion 1540 can be provided, for example, to facilitate cabling andmounting flexibility of the space transformer connector 1500. FIG. 15Aillustrates three edge connectors 1510 a-c adjacent pin-array field 1515and three edge connectors 1520 a-c adjacent pin-array field 1525. FIGS.15B and 15C illustrate side and end views of the edge connectorconfiguration, respectively. It will be appreciated that the number andlocation of edge connectors may be varied and the illustrated embodimentis not intended to limit various disclosed and claimed embodiments.Further, the edge connectors may be made of similar materials as the PCBin some embodiments or may be flexible circuit ribbon in otherembodiments or combinations thereof. The remaining aspects of the spacertransformer connector 1500 are similar to the previously disclosedembodiments. Accordingly, a detailed description will not be providedherein.

FIGS. 16A-C illustrate another configuration of the spacer transformerconnector 1600 having at least one PCB edge connector (1610, 1620) topermit external connections to selected signals passing between thedaughter card and the mother board. Referring to FIGS. 16A-C in additionto edge connectors 1610 and 1620, one or more shelf portions (e.g., 1630and 1635) may be formed to support the addition of one or moreactive/passive components (e.g., 1660 and 1665) directly coupled to thePCB forming the space transformer connector. The components 1660 and1665 in embodiments may be located on either side of the shelf portions1630 and 1635. In some embodiments the shelf portions 1630 and 1635 maybe formed from the same portion that used for the edge connectors 1610and 1620. Cut-out portions 1640 and 1645 can be provided, for example,to facilitate cabling and mounting flexibility of the space transformerconnector 1600. A pedestal 1670 may be provided between cutout portions1640 and 1645 to aid in supporting a DUT. Further, depending on theconfiguration pedestal 1670 may retain one or more conductive layersformed from a portion of the same PCB forming the spacer transformerconnector 1600. The one or more retained conductive layers may be usedfor various purposes such as routing signals and/or electromagneticshielding.

FIG. 16A illustrates one edge connector 1610 adjacent circular pin-arrayfield 1615 and an edge connector 1620 adjacent circular pin-array field1625. FIGS. 16B and 16C illustrate side and end views of the edgeconnector configuration, respectively. Once again, it will beappreciated that number and location of edge connectors may be variedand the illustrated embodiment is not intended to limit variousdisclosed and claimed embodiments. Further, the edge connectors may bemade of similar materials as the PCB in some embodiments or may beflexible circuit ribbon in other embodiments or combinations thereof.The remaining aspects of the spacer transformer connector 1600 aresimilar to the previously disclosed embodiments. Accordingly, a detaileddescription will not be provided herein.

It will be appreciated that information and signals may be representedusing any of a variety of different technologies and techniques. Forexample, data, instructions, commands, information, signals, bits,symbols, and chips that may be referenced throughout the abovedescription may be represented by voltages, currents, electromagneticwaves, magnetic fields or particles, optical fields or particles, or anycombination thereof.

It will be appreciated that space transformer connector, as discussedand illustrated in the foregoing disclosure and related figures, may beincluded within a daughter card/mother board assembly, an integratedcircuit test system a or any other device that interfaces two highdensity contact arrays. Accordingly, embodiments of the disclosure maybe suitably employed in any device which includes a space transformerconnector as disclosed herein.

The foregoing disclosed devices and methods may be designed andconfigured into GDSII and GERBER computer files, stored on a computerreadable media. These files are in turn provided to fabrication handlerswho fabricate devices based on these files.

Accordingly, embodiments can include machine-readable media orcomputer-readable media embodying instructions which when executed by aprocessor transform the processor and any other cooperating elementsinto a machine for fabricating the embodiments described herein asprovided for by the instructions.

While the foregoing disclosure shows illustrative embodiments, it shouldbe noted that various changes and modifications could be made hereinwithout departing from the scope of the invention as defined by theappended claims. For example, the various embodiments disclosed haveillustrated relatively straight through coupling of signals from pads ona first side through the vias to corresponding pads on a second side.However, it will be appreciated that the multi-layer PCB constructionallows for internal routing of signals (e.g., using blind and/or buriedvias) so the correspondence between pads on the first side may bechanged both in geometry (e.g., located in different relative positions)and number (e.g., one pad to two or more pads). Still further, thecapacitive and/or inductive AC coupling across a 3D-SpaceX connector ispossible by exploiting the flexibility of the 3D-SpaceX pad-array fieldand multi-layer PCB construction.

The functions, steps and/or actions of the method claims or describe inthe disclosure in accordance with the embodiments described herein neednot be performed in any particular order. Furthermore, although elementsof the embodiments may be described or claimed in the singular, theplural is contemplated unless limitation to the singular is explicitlystated.

1. A space transformer connector formed of a multilayer printed circuitboard (PCB) comprising: a plurality of ground planes separated by layersof dielectric material in the PCB; a plurality of conductive viasextending at least partially through the PCB; a pad-array field having aplurality of contact pads located on opposing surfaces of the PCB, whichare coupled to the conductive vias; and at least one coaxial mount foralignment and mounting, wherein the coaxial mount is located adjacentthe pad-array field.
 2. The space transformer connector of claim 1,further comprising: a remote integrated mount formed from the PCB,wherein at least a portion of the PCB is removed from an area betweenthe pad-array field and the integrated mount.
 3. The space transformerconnector of claim 2, wherein the portion of PCB removed includesmaterial around at least one-half of a perimeter of the pad-array field.4. The space transformer connector of claim 2, wherein the portion ofthe PCB removed is configured to mechanically isolate the pad-arrayfield to enable the pad-array field to achieve an independent mechanicalsteady state position.
 5. The space transformer connector of claim 1,wherein at least one of the pad and conductive via structures isconfigured for high frequency.
 6. The space transformer connector ofclaim 5, wherein ground and signal pads in adjacent rows can bealternated such that the signal pads oppose ground pads.
 7. The spacetransformer connector of claim 5, wherein ground and signal pads areoriented at an angle and separated a distance to facilitate high densityrouting.
 8. The space transformer connector of claim 7, wherein a degreeof row separation and inclination relates to a number and width ofadjacent traces allowable for given PCB mechanical and electricalcharacteristics.
 9. The space transformer connector of claim 5, whereinthe pad-array field is circular and wideband pads are located on acommon radius to allow for equal length transmission trace routing to RFconnectors.
 10. The space transformer connector of claim 5, whereinground vias are coupled to the ground planes and signal vias haveantipads formed in each ground plane.
 11. The space transformerconnector of claim 5, wherein ground vias are coupled to the groundplanes and coupled to pads that are arranged immediately adjacent toeach other in at least one row for at least a portion of the row. 12.The space transformer connector of claim 1, wherein the pad-array fieldsare configured in at least one of a symmetrical physical arrangement ora non-symmetrical physical arrangement.
 13. The space transformerconnector of claim 1, further comprising: a second pad-array located atan opposite end of the PCB from the pad-array field.
 14. The spacetransformer connector of claim 13, wherein each pad-array field is oneof circular, square, rectangular, or trapezoidal.
 15. The spacetransformer connector of claim 14, wherein each pad-array field iscircular and one is rotated about its axis with respect to the other, tofacilitate ingress and egress of signals.
 16. The space transformerconnector of claim 13, wherein each pad-array field has an inverseconfiguration of the other pad-array field.
 17. The space transformerconnector of claim 13, wherein there are at least two coaxial mount perpad-array field.
 18. The space transformer connector of claim 13,wherein at least a portion of the PCB is removed from an area betweenthe pad-array fields.
 19. The space transformer connector of claim 1,further comprising: an integrated mount formed from the PCB, wherein atleast a portion of the PCB is removed from an area between the pad-arrayfield and the integrated mount; and a device-under-test DUT supportpedestal located adjacent to at least one integrated mount position. 20.The space transformer connector of claim 19, wherein the DUT supportpedestal has PCB material milled away adjacent the DUT support pedestal.21. The space transformer connector of claim 1, further comprising: gluechannels adjacent the pad-array field configured to mechanically attacha conductive elastomer.
 22. The space transformer connector of claim 21,further comprising: a keepout region between the glue channels and thepad-array field.
 23. The space transformer connector of claim 21,wherein the glue channels are formed from grooves in the PCB material.24. The space transformer connector of claim 1, wherein the spacetransformer connector is positioned between a daughter card and a motherboard.
 25. The space transformer connector of claim 24, wherein thepad-array field is arranged to match contacts of least one of thedaughter card or the mother board.
 26. The space transformer connectorof claim 25, further comprising: a conductive elastomer disposed overthe pad-array field and configured to electrically couple the pad-arrayfield to the contacts of at least one of the daughter card or the motherboard.
 27. The space transformer connector of claim 26, wherein theconductive elastomer becomes conductive under a range of pressures. 28.The space transformer connector of claim 1, further comprising: at leastone edge connector located adjacent pad-array field.
 29. The spacetransformer connector of claim 28, wherein the PCB is includes aplurality of PCB layers and wherein the edge connector is formed fromone at least one of the PCB layers.
 30. The space transformer connectorof claim 29, wherein a layer forming the edge connector also forms ashelf portion in an opening formed by the portion of the PCB removed.31. The space transformer connector of claim 30, further comprising: atleast one active or passive component located on the shelf portion. 32.The space transformer connector of claim 28, wherein the edge connectoris located approximately in the middle of the PCB layers.
 33. The spacetransformer connector of claim 1, further comprising: a shelf portionformed in an opening, wherein the shelf portion is formed by at leastone layer of the PCB.
 34. The space transformer connector of claim 33,further comprising: at least one active or passive component located onthe shelf portion.
 35. The space transformer connector of claim 1,wherein at least one of the pads on one surface is coupled to at leasttwo pads on the other surface.
 36. The space transformer connector ofclaim 1, wherein at least one of the pads on one surface is coupled to apad on the other surface that is located in a different relativeposition.
 37. The space transformer connector of claim 1, wherein thePCB comprises: a daughter card formed from a plurality of conductiveplanes separated by layers of dielectric material in the PCB that extendbeyond the connector.
 38. The space transformer connector of claim 37,further comprising: a second connector portion having a pad-array fieldhaving a plurality of contact pads located on a second end of the PCB,which are coupled to conductive vias, wherein the PCB comprises aplurality of ground planes separated by layers of dielectric material inthe PCB, which extends beyond the layers forming the daughter card; anda second coaxial mount for alignment and mounting, wherein the secondcoaxial mount is located adjacent the second pad-array field.
 39. Anassembly comprising: a daughter card coupled to a device-under-test(DUT) configured to distribute signals from the DUT to a first contactarray; a mother board having a second contact array; a space transformerconnector formed of a multilayer printed circuit board (PCB) having aconnector portion comprising: a plurality of ground planes separated bylayers of dielectric material in the PCB; a first pad-array field havinga plurality of contact pads located on a first surface of the PCBconfigured to couple to the first contact array; a second pad-arrayfield having a plurality of contact pads located on a second surface ofthe PCB configured to couple to the second contact array; a plurality ofconductive vias extending at least partially through the PCB to couplethe first and second pad-array fields; and at least one coaxial mountfor alignment and mounting, wherein the coaxial mount is locatedadjacent the first and second pad-array fields; a first conductiveelastomer disposed over the first pad-array field, wherein the firstconductive elastomer is configured to electrically couple the firstpad-array field to the first contact array; and a second conductiveelastomer disposed over the second pad-array field, wherein the secondconductive elastomer is configured to electrically couple the secondpad-array field to the second contact array.
 40. The assembly of claim39 further comprising: a two-mount socket having two coaxial mounts foralignment and mounting, wherein the socket is configured to accept thedevice-under-test (DUT) and is coupled to the daughter card via the twocoaxial mounts.
 41. The assembly of claim 39, wherein the spacetransformer connector further comprises: an integrated mount portionformed from the PCB and configured to couple and align with the twocoaxial mounts of the two-mount socket, wherein at least a portion ofthe PCB is removed from an area between the connector portion and theintegrated mount portion.
 42. The assembly of claim 41, wherein theportion of the PCB removed is configured to mechanically isolate theconnector portion to achieve an independent mechanical steady stateposition relative to the integrated mount portion.
 43. The assembly ofclaim 42, wherein the portion of PCB removed includes material around atleast one-half of a perimeter of the connector portion.
 44. The assemblyof claim 41, further comprising: a DUT support pedestal located adjacentto the integrated mount portion.
 45. The assembly of claim 44, whereinthe DUT support pedestal has PCB material milled away adjacent the DUTsupport pedestal to allow for placement of electrical componentsadjacent the DUT pedestal.
 46. The assembly of claim 44, wherein the DUTsupport pedestal is configured to provide electrical shielding.
 47. Aspace transformer connector formed of a multilayer printed circuit board(PCB) comprising: means for providing ground connections separated bylayers of dielectric a dielectric means in the PCB; means for providingelectrical conductivity extending at least partially through the PCB;means for providing electrical contact having a plurality of contactpads located on opposing surfaces of the PCB, which are coupled to themeans for providing electrical conductivity; and means for aligning andmounting in an integrated unit, wherein the means for aligning andmounting is located adjacent means for providing electrical contact. 48.The space transformer connector of claim 47, further comprising: remotemeans for mounting formed from the PCB, wherein at least a portion ofthe PCB is removed from an area between the means for providingelectrical contact and the remote means for mounting.
 49. The spacetransformer connector of claim 48, wherein the portion of PCB removedincludes material around at least one-half of a perimeter of the meansfor providing electrical contact to mechanically isolate the means forproviding electrical contact to achieve an independent mechanical steadystate position.
 50. The space transformer connector of claim 47, whereinat least a portion of the means for providing electrical contactconductive via structures is configured for high frequency.